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A MEASURE OF LINKED - TRIP ACCESSIBILITY SURVEY IN WEST BERLIN

This paper was prepared for the First Conference of Australian Institutes of Transport Research, Monash University, December 1979. (IRRD no 239661). The difficulty in defining a precise meaning of accessibility has led to numerous such definitions being proposed in the literature. This paper will show that many of the proposed definitions of accessibility can in fact be gathered together to form a spectrum of accessibility measures. These measures differ with respect to the factors included in their formulation and their degree of behavioural interpretation. Existing measures of accessibility will be shown to be deficient in one major aspect. That is, they assume that for any one measure of accessibility there is but one origin of trips. Thus, in estimating the accessibility of a point within a region it is assumed that all potential trips, which contribute to the accessibility of that point, start from that single point. In view of the considerable amount of evidence demonstrating the widespread, and increasing, occurrence of trip - linking, such a proposition must be viewed as being rather doubtful. (TRRL) measure of accessibility which explicitly accounts for the linking of trips. The implications of this measure, compared to a conventional unlinked - trip accessibility measure, are discussed as are some problems which are foreseen in the practical implementation of such a measure